Final answer:
LOGO lights on an aircraft's external lighting panel are automatically illuminated during nighttime operations to increase visibility and identify the aircraft.
Step-by-step explanation:
The question asks about the operation of LOGO lights on an aircraft's external lighting panel (EXT LT PANEL). LOGO lights are typically used to illuminate the airline's logo on the tail of the aircraft.
These lights are not just for aesthetic purposes; they also increase the visibility of the aircraft for other aircraft while on the ground or in flight during the night. As for when these lights are automatically turned on, the correct answer is: C) During nighttime operations.
They are usually programmed to automatically illuminate once the ambient light levels fall below a certain threshold, indicating dusk or nighttime conditions, and they remain on until the light conditions meet daytime thresholds.